How can I increase the potential bounty/reward for my research?

The final offer sent by Crowdfense to acquire your exploit, after your submission is thoroughly reviewed and validated, will depend on the scope of the bug(s) (affected products, criticality, attack vector, required configuration, user interaction, limitations, etc), but also on the quality of the exploit (reliability, bypassed exploit mitigations, covered versions/systems/platforms, process continuation, no hardcoded offsets or ROP, etc).