Genghis
I guess I feel very strongly on the subject of headgear. There is NO substitute for a properly fitting helmet. The softhelmet you are looking at is designed to be used with a MK 1 Helmet. (still available from One of the mil surplus suppliers)
From a pink AIC a few years ago recommending headgear for Aeros/microlight pilots. Eighty percent 80% of fatal head injuries would have been prevented by the use of proper safety headgear. Just read the survivability section of the following very recent report.
http://www.aaib.gov.uk/publications/...52__g_yams.cfm
Deaths and serious injuries in aviation will only cause more restrictions on our sport from the authorities.
Genghis you are HIGHLY RESPECTED in this forum, I urge you to look at the options. You would never recommend anyone to skimp on engineering.
I do not mean to preach or open up the whole bonedome debate again, just perhaps think of the flying we all do. And make a judgement to the suitability of headgear.
You only get DEAD once.
Safe flying to all
Wide