That is a huge amount of money, and I think the best way is to buy chunks of bitcoin whenever the price drops back a little. 10 months is a long time and the market will drop at some point even if the market is recovering in a slow manner.

Honestly, only whales can give you a good answer regarding this. Trading a huge amount of money intended to push the market up for 10 months is not done by normal traders.

Interesting questions, you are considered a whale already with that huge amount, if you want to make a profit buy on one transaction but if you want to push the price then divide the 100 million in 10 months where you want to push the price, but one advice not to do it in one exchange alone, pick at least 3 to 5 top exchange in the market.

It's very simple, you just have to keep on buying with that period of time. Yes, buying for 10 months if your goal is to push the prices up. Although this is already a billion dollar market still that can help to push the price for few dollars.

There's no actual incentive that new/old traders should receive, this is a decentralized and a stand alone market so I don't think there's a need for everybody to have that incentive on your mind.

Well, look at what $15 000 000 worth of coins, did to the price in 1 day. <2000+ BTC that was dropped onto a single exchange> The global price took a nose dive, because it caused a ripple affect on other markets. 

So with $100,000,000 ...you might cause a massive increase in the price, if you do this on a single exchange over a short period, but markets react much quicker to a "dump" than a "pump". 

pushing the price up is just providing a big gap between the bottomline value and the ATH. you will always be fighting off speculators taking their profits and letting you pump it again for them to just raid you.

the best thing is not to push the speculative ATH up. but to keep the bottom corrections balanced/above a sane level. that way your fighting less people trying to raid you dry and your helping keep value up so that when community speculation returns there is not as much of a jump needed, thus prices remain higher and increase more naturally without needing to pump/get raided as much

EG
summer 2018 value was $5800~ and the price was over $6k. trying to pump the price to $8k thousands of people would have just raided you dry. then when it got cheaper to mine(value drop) to $3500~ in autumn. and price went down to near the same it would have taken much more to get things back up.

however. if you tried to keep value above $3500 in autumn then the community would have got to this months $8k much sooner and without raiding you dry

tl:dr;
dont pump the high's.. pump the lows

How can he deposit this huge money to OTC services. Which OTC service you have used?

I am interesting with OTC market. But I have no experience about it.