Horizons Unlimited - The HUBB - Rainy season East Africa

I'm doing London-Cape Town by motorbike starting in October and I have a year to do it. (Lucky me!) Just wondering how best to deal with the rainy season and would love any perspectives from peops here who have actually been to this part of the world!

Option A:
Go a bit faster through Egypt, Sudan, Ethiopia, Kenya (1 month per country) and then go really quick through Tanzania/Malawi in March (wet) to reach Mozambique just at the end of the rains, then loop back up through Tanzania and Zambia

Option B:
Go quite slow through 1st 4 countries (2 months per country) and then hit Kenya in June as the rains finish there - would then have to move a bit quicker through the remaining countries/miss a couple.

I suppose it depends what Kenya is really like to bike in June, what Tanzania/Malawi would be like to bike in March (sticking to tarmac I guess, assuming that's possible) and how you rate the countries north of the equator compared to those south. Anyway, curious to hear opinions.