The two substrate boats, {HEAD ~ each} configured to hold a set of substrates, may be assembled in a way that {TAIL ~ the two sets} of substrates interleave with one another 
The two substrate boats , { HEAD ~ each } configured to hold a set of substrates , may be assembled in a way that { TAIL ~ the two sets } of substrates interleave with one another
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH